Automotive airbags are known. Such airbags are designed to deploy inside a passenger compartment of an automobile during collisions to protect the occupants from injury.
In order to protect occupants from injury during high speed collisions, an airbag must deploy to occupy a passenger space between the passenger and source of impact. Further, before deployment, an airbag must be small enough to compactly fit within the upholstery of a protected automobile.
The airbag must deploy very rapidly also be reliable. After installation, the airbag must be capable of reliably deploying years later without the necessity of regular maintenance.
Airbags used today, typically include (as main operative components) a polyester airbag and inflation source. The inflation source is typically an ignitable gas generating material that is triggered upon detection of impact by a collision detector.
Once the gas generating material is ignited, the material burns very quickly, in turn generating a sufficient volume of gas to quickly deploy and fill the airbag. Within a few milliseconds, the gas generating material burns itself out and the airbag deflates.
In order to function properly, the gas generating material must be contained in a housing capable to tolerating the heat of combustion. Further, because of the speed of combustion and materials used, molten slag is frequently generated during the combustion process by the gas generating material. The slag must be filtered from the gas stream to avoid melting and causing failure of the polyester airbag during deployment.
Prior art airbag inflators have used metallic housings to contain the gas generating material. Ceramic filters have been disposed in a gas path to contain slag and reduce a gas temperature. While prior art airbag inflators have proved effective, they are heavy, bulky and relatively expensive to produce. Accordingly, a need exists for a filter for an airbag inflator which is relatively light and inexpensive to produce, but which provides the porosity and filtering characteristics of ceramic.